We anticipate that during the next year the correlation between the physiologic effects of a few specific agonists on the contraction-relaxation cycle of the uterine smooth muscle cell and their adenylate cyclase-regulating properties will be resolved. We have resolved the beta-adrenergic catecholamine sensitive adenylate cyclase system of the myometrium into its receptor, transducing, and enzymatic components. We will now proceed with determining the level at which E series prostaglands and muscarinic cholinergic agonists mediate cAMP production in response to the beta-agonist isoproterenol. These studies will be greatly facilitated by using smooth muscle plasma membrane fractions prepared by a purification procedure developed by us during the past year. The effects of these same analogs on contractility in the presence and absence of isoproterenol will then be determined under isotonic conditions in organ baths. Initially the results will be qualitative, and we will proceed to the more quantitative dose-dependent effects as our expertise improves. Depending on our progress during the next year, we will proceed in the same manner characterizing other agonists which have been shown to regulate both beta-agonist cAMP production and isoproterenol-induced relaxation of uterine smooth muscle.